Breakthrough new test for Down syndrome

Invasive procedures such as amniocentesis could be a thing of the past with recent news that a blood test performed during pregnancy is being developed to give the same results.

Currently, pregnant women who are considered at high-risk of giving birth to a baby with chromosomal or genetic disorders, such as Down syndrome, muscular dystrophy and cystic fibrosis, undergo an amniocentesis test during the fifteenth week of pregnancy.

While amniocentesis is considered extremely accurate - with a greater than 99% success rate - it also carries with it an increased risk of miscarriage. Experts estimate that by undergoing amniocentesis, a pregnant woman increases her risk of miscarriage from 1 in 250 to 1 in 300.

The new blood test will carry none of these risks and will be able to be performed as early as 6 weeks into pregnancy. As blood samples are taken during routine antenatal tests, this new test could be performed on high-risk women without any additional discomfort.

Still a few years off, experts all agree that the development of an affordable, reliable and non-invasive test for diagnosing Down syndrome and other chromosomal abnormalities is the holy grail of prenatal diagnosis.

Maternal screening

Currently, a combination of a blood test and an ultrasound called Nuchal Translucency, which measures the amount of fluid behind your baby's neck for high-risk indicators, can be carried out on pregnant women to identify those who may be at a higher risk of having a baby with Down syndrome. As the result of this testing, about 5% of women will receive results indicating that she has an increased risk. This testing does NOT confirm that your baby has Down syndrome - it merely returns a result that your baby is at higher risk.

It is at this point, that further testing is recommended to get a definitive result. There are two different tests that can be carried out:

Amniocentesis

Chorionic villus sampling (CSV)

and both carry the same risks of miscarriage.

Amniocentesis and CVS tests are not compulsory and the decision to undergo further testing - or not - rests with the pregnant mother.